Fire control apparatus



June 19, 1956 A. P. DAvls RIRE CONTROL APPARATUS 2 Sheets-Sheet l Filed Sept. l, 1936 lNvEN'roR -ZBZZY f WORNJ A. P. DAVIS FIRE CONTRL APPARATUS June 19, 1956 Sheets-Sheet 2 Filed Sept. l, 1936 United States Patent F CONTROL APPARATUS Arthur P. Davis, New York, N. Y., assignor to American Bosch Arma Corporation, a corporation of New York Application September 1, 1936, Serial No. 98,877

Claims. (Cl. 89-28) This invention relates to gun fire control apparatus and has particular reference to apparatus for automatically controlling the re of naval guns while compensating for errors in tiring time.

In firing certain types of naval guns, particularly antiaircraft and smaller guns, the gun is continuously pointed on the target, and loaded and fired as desired. By this means, irrespective of the roll of the ship, as many rounds may be fired as can be loaded in the time available. However, the main battery guns are not usually handled this way, but are depressed to a horizontal position for loading. Once loaded they are elevated to a computed angle and fired as the ship reaches a predetermined position, with respect to the horizontal plane.

As the projectile leaves the muzzle of the gun, the gun must be directed in a definite predetermined direction. This means that the elevation of the gun with respect to the deck, and the instant of ring, must be accurately controlled. The latter function is complicated by the fact that, due to the actual time of burning of the powder and other factors, there is a denite small interval of the time between the closing of the firing key and the passage of the projectile out of the gun, which is called the tiring delay. It is not suicient to close the ring circuit as the ship reaches the proper angular position, but rather the gun must be red ahead of this position by an angle whose magnitude depends upon the rate of roll of the ship and the tiring delay. The faster the ship iS moving in roll or pitch as it approaches this position, the greater the angle by which the firing must be advanced, so as to provide a constant advance in time.

In accordance with the present invention, automatic gun re control apparatus is provided in which the ring time for the guns is automatically advanced by an amount dependent upon the velocity of roll of the ship, so as to compensate for the tiring delay at that particular velocity of roll.

More particularly, the apparatus of this invention comprises a relatively iiXed contact and a relatively movable stabilized contact adapted to engage the relatively fixed contact to automatically fire the guns as the ship in roll approaches the even keel position, the amount of advance of the tiring time before the even keel position is reached being determined by a firing delay compensator adapted to displace the relatively fixed contact by an amount depending upon the velocity of roll of the ship. The stabilized contact moves with respect to the relatively fixed contact as the ship rolls, being connected to a fixed reference device, such as a stable gyroscopic element. Thus, as the uncompensated, stabilized contact moves toward the mid-position, representing the even keey position of the ship, it engages the relatively fixed, compensated contact, which has been displaced by the compensator in advance of mid-position, so that the guns are red ahead of the even keel position of the ship to compensate for the firing delay.

In a preferred arrangement of the invention, the relatively iixed, compensated contact is displaced in accordice ance with the relative stabilizing movement resulting from the fixed reference, and thus in proportion to the velocity of roll, by an advance imposed by the delay compensator, so that the stabilized contact overtakes the compensated contact at an earlier time as the ship approaches the even keel position, whereby the lire of the gun is advanced as described. This advance of the delay com'= pensator may be imposed electro-mechanically by an eddycurrent coupling, hydraulically, or otherwise. Where hand re is to be employed instead of automatic fire, index marks substituted for or associated with the ring contacts indicate the time for closing the manual ring key.

It will be seen that the tire-control apparatus of the invention provides an extremely effective means for compensating for the tiring delay for any rate of roll of the ship upon which the guns are mounted, so that their control is accurate under all normal conditions of motion of the ship, whether occasioned by the normal movement due to the condition of the sea, or by disturbances due to other causes, such as heavy gun fire and the like.

For a more complete understanding of the invention reference may be had to the accompanying drawings, in which:

Figure l is a schematic diagram of the gun lire control apparatus of this invention;

Fig. 2 is a perspective view, partially schematic, and partially in section of one form of the firing delay compensator; and

Fig. 3 is a perspective view, partially in section, of another form of ring delay compensator.

Referring to Fig. 1 of the drawings, numeral 10 designates the stable element consisting of a gyroscope that is normally vertical, suitably supported for universal movement in inner gimbal ring 11 and outer gimbal ring 12 which in turn is pivoted on a suitable support 13 secured to the deck of the ship or the like, so as to partake of its motion in roll or the like. Carried by the gyroscope 10, preferably in alignment with its vertical spin axis, is an alternating current magnet 14 adapted to induce a voltage in the follow-up coil 15 mounted directly above it on a frame 15 carried by the outer gimbal ring 12. Relative movement of the follow-up coil 15 to one side or the other of the magnet 14 as the ship rolls induces a voltage of corresponding sense in the follow-up coil 15 and is amplified at 16 for driving follow-up motor 17 in the corresponding direction and through a corresponding angle. This follow-up motor is connected by shaft 18 and gearing 19 to level shaft 20, operatively connected to the gimbal ring 12 for moving the latter through a follow-up angle so as to restore follow-up coil 1S to its normal neutral position in respect to the magnet 14. Thus the rate and angle of rotation of level shaft 2() conforms to the movement of the vessel in roll relatively to the stable element 10. Further details of the followup mechanism and the stable element are illustrated and described in copending application Serial No. 53,736, iiled December l0, 1935, which issued as U. S. Patent No. 2,421,247 on May 27, 1947.

The level angle Whichthe position of the level shaft 20 represents is the angular departure of the ship from the even keel position in a vertical plane through the line of sight on the target on which the guns to be red are directed. The level shaft 20 is employed in the arrangement illustrated to control the iire control apparatus of this invention, but it is to be understood that the crosslevel follow-up system, similarly actuated by the stable element 1t) may be employed with equal facility for that purpose. The angle developed by the cross level followlight of sight. Y

The automatic firing contacts designated 21 which may be called the relatively movable contact, and 22, which may be called the relatively xed Contact, are mounted on relatively movable insuating supports 23 and Z4 respectively, the former preferably constituting a disc and the latter a ring encircling the disc 24 and both rotating about a common axis 25. The ring 23 carrying the outer firing contact 21 is driven from the level shaft 2S through suitable gearing 26, shaft 27 and pinion 2S meshing with the toothed edge of ring 23. A mechanical differential 29 is interposed in shaft 27, whereby the mean position ci the outer contact 21 may be changed and the time of closure of the tiring circuit can be set for any desired point in the motion of the level shaft 2G or in the roll of the ship. The complete function of differential 29 will be described later. l

The Wires 30 severally connected to tiring contacts and 22 lead to the firing circuit which is energized when the contacts 21 and 22 engage. A switch key 31 bridged across the wires 30 may be employed where manual tiring is to be substituted for automatic firing. For the purpose of indicating the proper time of manual firing, index lines 32 and 33 are provided on ring 23 and disc 24, respec tively, and when these two index lines coincide, key 31 is adapted to be closed. Cooperating index marks 34 on ring 23 and 3S on stationary ring 36 coincide when the level angle is zero and there is zero input to the differential 29. Thus, for manual tiring when the ship is on even keel, index lines 3ft and 35 may be employed. Similarly, when follow-up coil is in alignment with magnet 14, no current flows in the follow-up circuit so that a galvanometer 37, bridged across it indicates zero. Thus, by means of galvanometer 37, which accordingly indicates the even keel position of the ship, manual firing by means of key 31 may be eifected. Both galvanometer 37 and indices 34 and 35 may be provided for alternative tiring in the event of failure of the tiring delay compensator, in which case the key 31 may be closed slightly ahead of zero position to compensate manually for tiring delay. If the follow-up fails, it is possible, by means of hand crank 88, to drive the follow-up mechanism, using the galvanometer 37 to indicate synchronism of the followaup system with the sensitive element. A selected angle may be set in the follow-up mechanism by hand, corresponding to the angle input to the differential 29 of the automatic contact 21, so that galvanometer 37 will thus indicate zero when the ship reaches its predetermined position in roll.

Compensation for firing delay is automatically introduced by the tiring delay compensator 3S interposed between aligned shafts 25 and 39, the former driving disc 24, while shaft 39 is connected to the level shaft 2t) by gearing 40. By means of the tiring delay compensator 38 the inner contact 22 is positioned on one side or the other of the even keel position, depending upon the direction of the roll, so that its position is advanced to meet the outer contact 21 in order to close the firing circuit 30 before the mid-position. Outer contact 21, being driven from level shaft has the oscillatory motion corresponding to the roll of the ship and is in mid-position normally when the ship is on even keel.

The displacement of inner contact 22 relatively to outer contact 21, effected by the tiring delay compensator 38, may be produced in several ways. In Fig. 2 one form of a firing delay compensating mechanism is illustrated in perspective. The outer firing contact 21 is shown carried by the toothed ring 23 driven by the pinion 28 connected to shaft 27 in turn connected through differential 29 and worm gearing 26 to the level shaft 20. The inner firing contact 22 is carried by an arm 24 mounted on shaft 25 connected to the tiring delay compensator 38, which is actuated from level shaft 20 through both gearing 40 and shaft 39.

The compensator 38 consists essentially of a rotating magnetic structure comprising an annular iron ring 41 mounted on shaft 39, so as to rotate therewith, and carrying a multi-polar rotor 42, the poles 43 of which are directed substantially radially as shown. The bevel gearing 49 for driving shaft 39 and consequently the rotor 42 is such as to drive the rotor 42 at approximately 90 times the rate of rotation of the level shaft 2t). The field coils d mounted on the poles 43, which may be four in number, are energized from a direct current supply 46 through slip rings i7 mounted on shaft 39 and suitably connected to coils 45. A potentiometer 4S, calibrated in hundredths of seconds of firing delay, is provided for adjusting the voitage supply to the field coils 45. The purpose of this aiment wili be described later.

Energization of the eld coils 45 in the manner described provides a radial field across the narrow air gap between poles 43 and iron ring 12.1. Bositioned in the air gap between the poles 43 and ring 41 is an annular at 49 of copper carried by a disc 50 secured to shaft 2.5, so that the ring 49 rotates in the air gap between the rotor i and ring 41 about an axis aligned with the axis of rotion of the ring 41. As the rotor 42 rotates, eddy-cur rerts are induced in the copper ring 49 which tend to carry it around with the rotor 42, causing a rotation of shaft 25, arm 24 and inner firing contact 22.

The rotation of the ring 49, however, is restrained by two springs S1, each connected at its outer end to a suitable support 52 and at its inner end to an arm 53 secured to disc Sti carrying the ring 49, so that springs 51 operate in opposite directions and tend to restrain the ring 49 in a relatively xed mid-position. A damping vane 54 carried by an arm 55 secured to disc 50 of ring 49 and oscillating in a container 56 of oil or other viscous uid, damps the motion of the ring 49. A latch 57 may be slipped over arm 55 to lock the firing delay compensator 38 with the corresponding firing contact 22 in mid-position.

in operation, as the rotor 42 and poles 43 are driven in accordance with the stabilizing movement of level shaft 2Q, eddy currents are induced in the copper ring 49, which tend to and do, to a limited extent, carry the latter around with the rotor 42 and accordingly the arm 24' and the inner tiring contact 22 are advanced. For constant field strength the voltage induced and the eddy-currents that fl w in ring 49 are proportional to the speed. Thus the developed torque is proportional to speed and, with the linear restraining torque due to the springs S1, the angle through which the arm. 2li and inner firing Contact 22 is turned is Vproportional to the speed of level shaft 2). Since disc 23 and outer tiring contact 21 are driven by level shaft 2i?, the angle that the inner firing Contact 22 is advanced to meet the outer tiring Contact 21 is proportional to the actual velocity of roll of the ship, and the interval by which the time of closure of the two tiring contacts 21 and 22 is advanced is constant irrespective of the period or angle of roll of the ship.

The time interval by which the firing is advanced to compensate for the tiring delay is adjustable by varying the Voltage applied to the eld coils 45 bymeans of the potentiometer 48, which is calibrated in hundredths of seconds of firing delay. This varies the flux and the torque `due to the eddy-currents developed in ring 49 and accordingly controls the angle of advance of the inner contact 22 for a given velocity of roll of the ship. By adjusting the differential 29 by means of shaft 58 connected thereto, the mean position of the outer firing contact 21 can be changed and the time of closure of the firing circuit can be set for any desired point in the motion of the level shaft 2t) or in the roll of the ship. By means of shaft 58 a correction from the pointers instrument or the crosslevel instrument may also be introduced.

In the modified form vof the firing. delay compensator illustrated in Fig. y3, which is hydraulically controlled, the displacement of the inner tiring-contact 22 carried by disc 24" is again made proportional to the actual velocity of the ship in roll, but in a different way. This mechanism comprises a casing 59 fitted with rollers 60supported on rails-61, so that the casing 59 may oscillate,but its oscillationis restrained by opposed Vcentering springs 62 connected at their opposite ends to a suitable stationary bracket 63. t

The casing 59 is hollow, providing a cylinder 64 arranged parallel to the path of movementV of the casing 59 and containing two pistons 65 spaced apart and connected by the rack 66. The two opposite ends of the cylinder 64 beyond the pistons 65 are connected by a passage 67 and are filled with oil or other liquid. The flow of oil between the opposite ends of the cylinder 64 through the passage 67 is controlled by a valve 68, which is adjustable by acalibrated knob 70, cooperating with stationary index mark 71. Rotation of the valve 68 by means of knob 70 varies the resistance to the flow of oil between the opposite ends of the cylinder 64 through passage 67.

Meshing with rack 66 is a pinion 72 carried by shaft 73 journalled in bracket 63 and driven by cross-level shaft 20, through gearing 74 onsleeve '75 and pinion 76 meshing therewith and connected to shaft 73. Sleeve 75 is provided with an arm 77 carrying the outer firing contact 21, which accordingly is driven directly from the level shaft 20.

Secured to frame 59 is a rack 78 for rotating a pinion 79 as the frame 59 oscillates and this pinion is carried by shaft 80 journalled on frame 63 and carrying gear 81, which through gear 82, drives disc 24 carrying the inner tiring contact 22', the disc 24 being supported on a shaft 85 freely rotatable on bracket 63, while the upper end of shaft 80 and the shaft 83 of gear 82 are journalled on an extension 84 of frame 63.

In operation, with the pistons 65 continuously driven by the level shaft 20, the velocity of the pistons 65 is proportional to theangular rate of motion of the ship. With the proper adjustment of valve 68, opposing the relatively low resistance to the ow of the oil, so that the displacement of the frame 59 is small compared to that of the pistons 65, the pressure developed by the motion of the pistons65 is directly proportional to their velocity. Inasmuch as the frame 59 is free to move except as restrained by centering springs 62, the movement imparted thereto bythe oil under pressure is proportional to this pressure and is therefore proportional to the angular rate of motion of the ship.

This movement of the frame `59 is transmitted by rack 78, pinion 79, shaft 80 and gears 81 and S2 to the disc 24 carrying the inner tiring contact 22', which is accordingly advanced the proper angle to advance the tiring time for the gun in compensation for the firing delay. The factor of proportionality between the movement of the casing 59 and the pressure of the oil therein effecting this movement, or, in other words, the tiring delay compensation interval, can be adjusted. by changing the restriction to the ow of oil in passage 67 offered by valve 68 simply by resetting the valve by means of the knob 70, which is calibrated in hundredths of seconds of firing delay compensation.

An index 86 on the frame 59 cooperates with a stationary scale 87 calibrated in minutes of arc of firing delay compensation and is adapted to indicate the arc corresponding to the movement of frame 59.

Other forms of mechanisms which will provide a displacement between the firing contacts, proportional to the actual velocity of the ship, may be substituted, but the two forms illustrated and described in connection with Figs. 2 and 3 will suffice to illustrate the principle of operation necessary to secure effective compensation for firing delay, Thus, in each case in normal service, guns will be fired by the automatic firing mechanism including the contacts 21 and 22, the outer one of which, 21, has an oscillatory motion corresponding to the roll of the ship and is in mid-position when the ship is on even keel. The inner contact, 22, is displaced on one side or the other of its zero or even keel position, depending on the direction of the roll, being advanced to meet the outer contact 21 in order to close the circuit before the mid-position.

tact reaches its mid-position.

In the event of failure of the firing delay compensator for any reason, the inner contact 22 can be locked in mid-position, as by the latch 57 illustrated in Fig. 2, and then the circuit will be closed when the outer con- An advanced xed angle of closure, corresponding to the firing delay, can be set by means of the differential 29 in the input to the outer contact 21 as seen in Fig. 1. Hand firing, by utilizing index marks 32 and 33 or the galvanometer 37 as indices, may be effected when the ship is on even keel, tiring delay being then introduced by closing the key 31 slightly before the index 32 coincides with mark 33 or the pointer of galvanometer 37 reaches zero position.

Although several preferred embodiments of the invention have been illustrated and described herein, it is to be understood that the invention is not limited thereby, but is susceptible of changes and detail within the scope of the appended claims.

I claim:

l. In fire-control apparatus for a gun mounted on an unstable support, the combination of stable means on the support, means movable in accordance with the movement of the support relatively to said stable means, a relatively fixed indicating member on the support, a relatively movable indicating member adapted to align with the relatively xed member, operative connections between said movable member and said movable means, and means responsive to the velocity of movement of the movable means for displacing the relatively fixed member to advance the time of alignment of -the relatively movable member therewith, said members being adapted to indicate the time of tiring of the gun by their alignment.

2. In fire-control apparatus for a gun mounted on an unstable support, the combination of stable means on the support, means movable in accordance with the movement of the support relatively to said stable means, a relatively fixed contact and a movable contact associated therewith, said contacts being adapted to fire the gun upon engagement, operative connections between said movable means and said movable contact, an element driven by said movable means, a second element operatively connected to the relatively fixed contact, electrical means creating a resistance to relative movement between said elements to effect displacement of the second element in accordance with the velocity of movement of the first element, whereby the relatively xed contact is displaced to vary the time of engagement between the contacts.

3. Invre-control apparatus for a gun mounted on an unstable support, the combination of stable means on the support, means movable in accordance with the movement of the support relatively to said stable means, a contact which is fixed with respect to the support and a movable contact associated therewith, said contacts being adapted to lire the gun upon engagement, operative connections between said movable means and said movable contact, an element driven by said movable means, a second element operatively connected to the relatively xed contact, a fluid connection between said elements responsive to the velocity of movement of the first element for displacing the second element accordingly whereby the relatively fixed contact is displaced to vary the time of engagement between the contacts.

4. In fire-control apparatus for a gun mounted on an unstable support, the combination of stable means on the support, means movable in accordance with the movement of the support relatively to said stable means, a contact which is fixed with respect to the support and a movable contact associated therewith, said contacts being adapted to tire the gun upon engagement, operative connections between said movable means and said movable contact, a iiuid column, operative connections between said column and said movable means, means resisting the movement of the column by said movable means, means responsive to the reaction of said column to the resisting means, and operative connections between said reaction responsive means and said relatively tixed contact, whereby the relatively xed contact is displaced to vary the time of engagement between the contacts.

5. In lire-control apparatus for a gun mounted on an unstable support, the combination of stable means on the support, means movable in accordance with the movement of the support relatively to said stable means, a Contact which is fixed with respect to the support and a movable contact associated therewith, said contacts being adapted to lire the gun upon engagement, operative connections between said movable means and said movable contact, a movable chamber containing a fluid, a piston for moving the fluid out of said chamber, a valve controlling the movement of the fluid, the resulting reaction to the flow of which causes the chamber to move in accordance with the velocity of said fluid ow, and operative connections between the chamber and said relatively xed contact, whereby said relatively xed contact is `displaced to vary the time of engagement between the contacts.

6. In a re control apparatus for an electrically-tired gun mounted on a rolling support, the combination of a manual switch for energizing the firing circuit of said gun, a stable means on the support, a member movable relatively to the stable means, an electrical element on the member, a cooperating electricalI element Von the stable means, said elements developing a voltage upon relative displacement, an indicator responsive to the voltage so developed for indicating the relative .displacement between the stable means and the support, and means for moving the member to obtain an indication by said indicator of a predetermined position of the support in roll for actuating said tiring switch.

7. In a re control apparatus for an electrically-tired gun mounted on a rolling support, the combination ofa manual switch for energizing the firing circuit of said gun, a stable means on the support, a member movable relatively to the stable means, an electrical element on the member, a cooperating electrical element on the stable means, said elements developing a voltage upon relative displacement, a motor energized by the voltage so developed, operative connections between the motor and the member for causing the member to follow the relative movement of the stable means, and an indicator responsive to the magnitude of the voltage so developed for indicating a predetermined position of the support in roll as an indication for actuating said firing switch.

8. In fire-control apparatus for a gun mounted on an unstable support, the combination of stable means on the support, means movable in accordance with the movement of the support relatively to said stable means, a relatively fixed contact and a movable contact associated therewith, said contacts being adapted to tire the gun upon engagement, operative connections between said movable means and said movable contact, an element driven by said movable means, a second element associated with said first element, driving` connections between said elements variable in accordance with the velocity of the rst element for displacing the second element different distances in accordance with said velocity, and eddy current operative connections between said second element and said relativelytixed contact, whereby the latter is displaced to advance the time of engagement between the contacts proportionally to a function of said velocity.

9. In lire-control apparatus for a gun mounted on an unstable support, the combination of stable means on the support, means movable in accordance with the movement of the support relatively to said stable means, a relatively fixed contact and a movable contact associated therewith, said contacts being adapted to tire the gun upon engagement, operative connections between said movable means and said movable contact, an element driven by said movable means, a second element connected to said relatively-xed contact, and eddy current operative connections between said element variable in accordance with the velocity of relative movement between them for displacing the second element accordingly, whereby the relatively fixed contact is displaced to vary the time of engagement between the contacts proportionally to a function of said velocity.

10. In a fire-control apparatus for a gun mounted on a rolling support, the combination of electrical means responsive to the roll of the support for firing the gun at a predetermined position of the support in roll, and eddy current means responsive to the velocity of roll of the support for adjusting the tiring Ymeans to advance the n'ng time ahead of said predetermined position proportionally to a function of the velocity of the roll.

References Cited in the le of this patent UNITED STATES PATENTS 678,757 Obry July 16, 1901 719,857 Von Pechy et al Feb. 3, 1903 1,445,191 Akemann Feb. 13, 1923 1,575,606 Henderson a Mar. 2, 1926 FOREIGN PATENTS 121,494 Great Britain L Dec. 24, 1918 

